Valve

ABSTRACT

A multi-position valve which provides throttling control. The valve includes a manifold having a first cylinder port, a second cylinder port, an exhaust port, an inlet port, a first valve port between the inlet port and the first cylinder port, a second valve port between the exhaust port and the first cylinder port, a third valve port between the inlet port and the second cylinder port, and a fourth valve port between the second cylinder port and the exhaust port. A plurality of valve rods, one of each is positionable in each of the valve ports, regulates the flow of fluid through the valve ports. Each pair of valve rods between the inlet and exhaust ports of each of the cylinder ports is connected to a yoke. A spring contacts each of the yokes to urge the respective valve rods into a closed attitude relative to the respective valve ports.

United States Pate 11 1 1111 3,726,31 Wogmam 51 Apr. 10, 1973 [54] VALVE471,805 9 1937 Great Britain ..137/596.2 [76] Inventor: James N. Wognum,9309 South Pleasant Avenue, Chicago, Primary Examznerl-Ienry T. Klmksiek60620 Assistant Examiner-Robert J. Miller Att0rney-Stone, Zummer & Aubel[22] Filed: June 7, 1971 121 Ap No.: 150,405 ABSTRACT A multi-positionvalve which provides throttling con- 52 11.s.c1 ..137/596.2, 137/6361trol- The valve includes a manifold having a first 51 1111. c1 ..F16k11/00 cylinder p r a second cylinder port, n exhaust p 581 Field 61Search ..137/596, 596.2, 636, an inlet port, a first valve P between theinlet p 137/636 1 and the first cylinder port, a second valve portbetween the exhaust port and the first cylinder port, a [56] ReferencesCited third valve port between the inlet port and the second cylinderport, and a fourth valve port between the UNITED STATES PATENTS secondcylinder port and the exhaust port. A plurality 346,913 '8/1886Heiss..... ..137/596 of valve rods, one of each is positionable in eachof 1,836,740 12/1931 Albers ..137/596.2 the valve ports, regulates theflow of fluid through the 2,214,271 9 0 Came ota-m .-.l37/636.l X v'alveports. Each pair of valve rods between the inlet genus 1 and exhaustports of each of the cylinder ports is con owe 2,409,765 10/1946 Kehl..137 s96.2 x mated to a yoke A Spnng contacts each of the Yokes FOREIGNPATENTS OR APPLICATIONS to urge the respective valve rods into a closedattitude relative to the respective valve ports.

6/1950 Czechoslovakia ..l37/596.2 18 Claims, 16 Drawing Figures 110 26102 122 98 9s 36 10s 49 86 e fi s. S 106 r 1- a\\;fi\ix gg $mqigh1:11 I

'\\\\\\\1 M 66 T 2 '4 I'IIII \11 [Aillf 22 11111 c3111. 1 1 1 14s z' V 1gi s-Q is ui-t 1111 ki zzmrll/miisnsmim PATENTED APR 1 OIQYS FIG. I4

FIG. 15

//VVE/VTOR.' JAMES IV. WOG/VUM fiw, 9W1: KW

Attorneys VALVE BACKGROUND OF THE INVENTION In many applications offluid-powered devices, it is necessary to effect a fine control ofcertain devices, such as, lifts, rams, clamps and booms. The controlsystems for these fluid-powered devices include what is commonly knownas a three-way or a four-way valve. The normal construction of athree-way or four-way valve is a spool-type valve or a disc-type valve.These valves operate quite satisfactorily in a go, no-go operation, thatis, when they are either on or off. It may be appreciated that in manyapplications, it is required to slow down the operation of a device sothat the device will move at a very slow rate. The use of spool-type ordisc-type valves for a throttling operation is not satisfactory becausethe change in rate of fluid flow is relatively large for smallincrements of movement of the valve control lever. This gives a jerkyflow of fluid to the operating device and thus results in a jerky motionof the controlled device. In many instances, this type of motion is notonly unsatisfactory but completely disruptive to the normal operation ofthe device.

SUMMARY OF THE INVENTION The valve construction disclosed hereinprovides a three-way or a four-way flow control valve. The valveutilizes a manifold which has an exhaust port and an inlet port. Anappropriate number of cylinder ports are provided. Valve ports providecommunicating paths between the inlet port and cylinder port and betweenthe exhaust port and cylinder port. The valve ports have valve rodspositioned in each of the ports to regulate the rate of flow of fluidtherethrough. An important aspect of the invention is that thepositioning of the valve ports and valve rods is such that the flow ofliquid through each valve port is always against the respective valverod. Springs are connected to the valve rods to urge the valve rodstowards a closed position. A cam is selectively connectable with thesprings for retracting selected springs, thereby allowing the force ofthe liquid to push back a selected valve rod toopen a given valve port.

In a four-way valve construction, there are two pairs of rods and therods of eachpair are interconnected by yokes which pivotedly engage therespective rods. The rods with the yokes are urged toward a closedattitude by springs. However, the connection between the springs and theyokes is also a pivotal connection which allows the yokes to pivot andthereby have'a balanced force on the yokes through positioning of thevalve rods in the valve ports. It is therefore a principal object ofthis invention to provide an improved valve construction having athree-way or four-way valve control which allows the valve to provide asmooth throttling flow through the valve without chatter.

It is another object of the present invention to provide an improvedvalve construction which allows a balanced flow of liquid to flow fromone side of a hydraulic cylinder to another.

It is a still further object of .the herein-disclosed invention toprovide an improved valve construction which may be easily manufacturedand conveniently assembled.

It is another object of the instant invention to provide a valve whichis lever-controlled and is spring-centered.

It is a still further object of this invention to provide alever-controlled valve which will remain in a selected position.

Other objects and uses of the present invention will become readilyapparent to those skilled in the art upon a perusal of the followingspecification in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of afour-way valve embodying the present invention;

FIG. 2 is a cross-sectional view taken on Line 2-2 of FIG. 1, showing aside elevation of a portion of the valve of FIG. 1;

FIG. 3 is a cross-sectional view taken on Line 3-3 of FIG. 2, showing across-sectional plan view of the valve shown in FIG. ll;

FIG. 4 is similar to FIG. 3, but showing a cam in an operative positionto retract one of the springs of the valve;

FIG. 5 is an enlarged view of one of the ports of the valve and aportion of one of the valve rods;

FIG. 6 is an enlarged cross-sectional view, showing a valve rod in aclosed attitude in one of the ports;

FIG. 7 is similar to FIG. 6, but showing the valve rod of FIG. 6 in apartially retracted position to show the throttling flow position;

FIG. 8 is a cross-sectional view taken on Line 88 of FIG. 3, showing anexhaust port and a pair of branches from the exhaust port;

FIG. 9 is a cross-sectional view taken on Line 99 of FIG. 3, showing apair of cylinder ports;

FIG. It is a cross-sectional view taken on Line 10- 10 of FIG. 3,showing an inlet port and a pair of branches;

FIG. 11 is a cross-sectional view taken on Line ll 11 of FIG. 8, showinga first cylinder port and the interconnection with the inlet port andthe exhaust port;

FIG. 12 is a cross-sectional view taken on Line 12-- 12 of FIG. 8,showing the interconnection of a second cylinder port with an inlet portand an exhaust port;

FIG. 13 is a perspective view, showing the valve of FIG. ll connected toa hydraulic cylinder;

FIG. 14 is a plan cross-sectional view of a valve embodying theherein-disclosed invention;

FIG. 15 is a side elevational view of a manifold block of FIG. 1d; and

FIG. 16 is a cross-sectional view taken on Line 16-- 16 of FIG. 14.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,and especially to FIG. 1, a four-way hydraulic valve embodying thepresent invention generally indicated by numeral 20 is shown therein.The valve 20 generally includes a manifold block 22, a cam block 24connected to the manifold block, a spring block 26 connected to the camblock, four valve rods 28, 30, 32 and 34 slideably mounted in themanifold and cam blocks, a valve operator 36 urged against the valverods 28 and 30, and a valve operator 38 urged against the valve rods 32and 34. A cam assembly 40 is mounted in the cam block 24 for engagementwith the valve operators.

The construction of the manifold 22 may be best seen in FIGS. 8 through12. As may be seen in FIG. 10, the manifold 22 includes an inlet port 42which is particularly adapted for connection to a source of hydraulicfluid under pressure. The port 42 has a threaded opening 44 to provide asuitable means for connecting the port to an appropriate hydraulicfitting. FIG. 8 shows an exhaust port 46 which has a threaded opening 48for connection to a hydraulic fitting. Positioned between the inlet portand the outlet port 46 is a first cylinder port 50 having a threadedopening 52 on one side of the manifold and a second cylinder port 54having a threaded opening 56 on the other side of the manifold. The axisof the cylinder ports 50 and 54 are parallel to each other and arepositioned between the inlet and outlet ports. Looking now to FIG. 11,the first cylinder port 50 is shown with its connections to the inletport 42 and the exhaust port 46. The inlet port 42 has a branch 58,which branch is parallel to the first cylinder port 50. A first valveport 60 is positioned between the branch 58 of the inlet port and thecylinder port 50. The valve port 60 has aligned therewith an axial rodaperture 62 which extends from the branch 58 to the side wall of themanifold. The valve rod 28 is slideably mounted in aperture 62 and ispositionable in valve port 60 to regulate the flow of a hydraulic fluidtherethrough. The exhaust port 46 has a branch 64 which is also parallelto the first cylinder port 50. A second valve port 66 is positionedbetween the branch 64 and the first cylinder port to providecommunication between the first cylinder port and the exhaust port 46. Asecond axial rod aperture 68 is aligned with the second valve port 66 toreceive the valve rod 32. The valve rod 32 regulates the flow throughvalve port 66.

Turning now to FIG. 12, the second cylinder port 54 is shown thereinconnected to the inlet port 42 and the exhaust port 46. The inlet port42 includes a branch 70. A third valve port 72 is positioned between thebranch 70 and the second cylinder port 54 to provide a communicationpath between the branch 70 and the second cylinder port 54. The exhaustport 46 has a branch 74 communicating therewith, which branch 74 isparallel to the second cylinder port 54 and the branch 70. A fourthvalve port 76 is positioned between the branch 74 and the cylinder port54 to provide a communicating path between the second cylinder port andthe exhaust port 46. A pair of parallel axial valve rod apertures 78 and80 is aligned with the valve ports 76 and 72, respectively, forreceiving the valve rods 34 and 30, respectively. Aligned with each ofthe axial valve rod apertures 62, 68, 78 and 80 is an axial sealingrecess 82 which receives a sealing assembly 84 for sealing the spacebetween respective valve rod to the manifold.

The cam block 24 includes a plurality of screw apertures 86 and a pairof yoke apertures 88. A yoke 90 is positioned in one of the yokeapertures 88 in engagement with the valve rods 28 and 30. A second yoke92 is positioned in the other yoke aperture 88 in engagement with thevalve rods 32 and 34. All of the valve rods are pivotedly engageablewith the respective yokes.

The spring block 26 has a plurality of screw apertures 94 which arealigned with the screw apertures 86 and have positioned therein screws96 which secure the spring block and the cam block to the manifold. Thespring block 26 has a pair of spring recesses 98 with an axial aperture100 aligned with each recess. A spring plunger 102 is positioned in oneof the spring recesses, with one end in the respective axial aperture100. A second spring plunger 104 is positioned in the other springrecess and has the other end positioned in the respective axialaperture. The spring plunger 102 includes a hollow body 106 with aninternally threaded head 108 formed integral therewith. A compressionspring 110 is mounted on the body 106 in engagement with the head 108.The spring 110 constantly pushes the head 108 toward the yoke 90. Theplunger 104 is identical in its construction to the plunger 102 in thatit also includes a hollow body 112 with an internally threaded head 114formed integral therewith. A compression spring 116 is mounted on thebody 112 in engagement with the head 114 to urge the head 114 constantlytoward the yoke 92. The head 108 has a camming surface 118 formedthereon, and the head 1 14 has a like camming surface 120 formedthereon.

A pivot pin 122 is threadedly mounted in the head 108 and has a pivothead 124 positioned in a pivot head recess 126 of yoke 90. A like pivotpin 128 is threadedly mounted in the head 114 and has a pivot head 130positioned in a pivot head recess 132 of yoke 92.

The cam assembly 40includes a cam 134, which is pivotedly mounted in thecam block 24. The cam 134 includes a camming surface 136 which isengageable with the camming surface 118 and a camming surface 138 whichis engageable with the camming surface 120. The cam also includes a camrecess 140 between the camming surfaces 138 and 136, which recess allowsthe cam to be rotated to achieve a maximum displacement of one of thespring plungers without affecting the other. The cam is fixed to androtates with a cam post 142 which has fixed thereto an arm 144. A handle146 is fixed to the arm 144 to provide a convenient means for turningthe cam.

Each of the valve rods 28, 30, 32 and 34 has an identical sealing end,which is best shown in FIGS. 5, 6 and 7 and will be described in detailherein. Each of the four valve ports 60, 66, 72 and 76 also has anidentical construction, which is best seen in FIG. 5 and will bedescribed in detail hereinafter. Referring now to FIG. 5, each valve rodincludes a valve rod body which has on one end a tapered bevel or crown150 extending to a tapered nose 152. It may be seen that the nose 152has a tapered portion for reasons which will become apparenthereinafter. It should be noted that the angle between the bevel and thebody, which is identified as angle A, is in this instance 29.5. Eachvalve port includes a passage 154 and a rod aperture 156 with a valveseat 158 between the passage 154 and the rod aperture 156. The seat 158is beveled, and the angle of the bevel between the axis of the openingis identified as angle B in FIG. 5 and in this instance is 30. It shouldbe noted that when each of the seats is formed, it is formed at an angleof 30 and the taper of the crown 150 of each of the rods is at an angleof 29.5. When the valve is initially assembled, the difference in theangles of the two tapers causes the crown 150 to be coined into the seat158 so that there is a perfectly snug fit between the parts, therebyproviding a perfect seal which does not allow fluid to leak past themating surfaces of the rod and port.

Looking now to FIG. T3, which shows an application of the valve 20, itmay be seen how one of the cylinder ports may be connected to a cylinder160 through piping T62, and the other cylinder port is connected to theopposite end of the cylinder 166 by piping 164.

It may be appreciated that the manifold 22 may be simply andeconomically manufactured. The inlet port 42 is drilled into the blockof the manifold, and the threaded opening M is threaded therein. Thebranches 58 and 70 are drilled into the manifold, and the open ends arethen plugged. The outlet 46 is also drilled into the block parallel tothe inlet port, and branches 64 and 74 are drilled into the manifold,intersecting the outlet. The open ends of the branches are also plugged.The cylinder ports 50 and 50 are also drilled into the block, and thethreaded openings 52 and 56 are threaded into the opening. The axial rodapertures 62, 68, 78 and 80 are drilled into the port, and theappropriate valve ports are also drilled and the seats are formed. Itmay be appreciated that all of these drilling operations may be donesimply and economically to provide an operative manifold.

it may be appreciated that the instant valve construction may be simplyand economically assembled, and that the adjustment of the particularvalve may be easily accomplished by moving the two pivot pins 122 and128 axially relative to the spring plungers 102 and 104 to apply thespring force to the yokes 96 and 92 and the valve rods which are inrespective engagement with the yokes.

When it is required to move the rod of the cylinder 160 inward, thehandle M6 is moved in the direction shown in FIG. 4 so that the camsurface 136 engages the cam surface 118 of the plunger 102 to push backthe plunger against the force of the compression spring 110. This allowsthe pressure of the fluid on the inlet port to force the valve rod 28 tothe left to the attitude shown in FIG. 45, thereby allowing fluid toflow to the cylinder and force a piston in the cylinder to the left, asviewed in FIG. I3. It may be appreciated that the fluid behind thepiston is then pushed through piping 162 into the other cylinder port,and thus a force is applied to the end of the valve rod 30. Since theforce of the spring on the yoke 96 is relieved by the action of the cam134, the force of the fluid displaces the rod until it engages the yoke96, allowing the fluid from behind the piston to be expelled out throughthe valve port 76 and to the exhaust port 46. It is important to notethat since the rod of the cylinder 160 is also being drawn in at thesame time, much more liquid must be expelled from behind the piston asliquid is added to the piston for the same amount of movement of thepiston in the cylinder. The instant arrangement allows for a balancingof the operation of the valves. As the pressure is built up behind thepiston, the rod 30 is pushed out further than the rod 28 since the yoke90 can pivot on pivot head 124, thereby achieving a balanced flow of Itis also important to note that the present construction allows theinstant valve to be used in a throttling operation. FIG. 6 shows a valverod in a completely closed or seated attitude, whereby there is no flowof fluid. It may be appreciated that by appropriate rotation of the cam134, the appropriate spring may be retracted only slightly so that thepressure of the fluid pushes the nose of the rod out only slightly tothe attitude such as that shown in FIG. '7, wherein the nose 152 isstill in the passage 154, restricting the flow of fluid through thatpassage and to have a limited flow. It is important to note that theflow of fluid is in the same direction as the direction in which thevalve rod is displaced, thereby eliminating chatter of the valve rod,thus providing a smooth and uniform flow of the fluid. This particulararrangement allows the flow of fluid to be even a minuscule flow, but ata steady, even rate which allows a very fine throttling of a devicewhich is operated by a fluid.

The valve 20 is adjusted to an open center very simply so that the portsare selectively closed. In order to make the valve an open-center valve,the pivot pins I22 and 128 are retracted in their respective plungerheads i180 and 114 by inserting a tool into the respective hollow bodiesand turning the pivot pins. When the pivot pins 122 and 128 are pulledback, the valve rods are pushed back by the fluid flowing through thevalve ports, also pushing back the respective yokes. Thus, there is aflow of liquid constantly through the valve .ports. Since the valve rodsare retracted, the springs 116 and I16 hold the plunger heads inengagement with the cam 134.

In order to close a pair of valve ports, the cam 134 is rotated, whichretracts further one of the spring plungers and allows the other springplunger to move toward the valve ports, thereby positioning the nose ofeach of the valve rods connected to the other spring plunger into itsrespective valve port. When the cam is sufficiently rotated, a pair ofvalve ports is closed. it may be appreciated that in this instance thetwo camming surfaces 136 and 138 are in constant engagement with therespective heads and the cam disengages the head only when one of theyokes is in a position wherein the valve ports are completely closedsince it is necessary for the valve rods to seat completely to preventfurther inward motion of the spring plunger.

It is apparent that the pivot pins need not be retracted to such adegree that the noses of the respective valve rods are completely out ofthe valve ports. Thus, there may be a very fine control of the flow offluid through the valve ports without any chatter of the valve.

Referring now to FIGS. M through 16, a three-way valve generallyindicated by numeral 266 embodying the present invention is showntherein. Valve 200 generally includes a manifold block 262, a cam block264 and a spring block 206 with a valve operator 266 mounted therein.

The manifold block 202 includes a cylinder port 210 having a threadedopening 212 for receiving a fitting.

An inlet port 2M opens on one side of the block, and an exhaust block216 opens on the same side of the block. A first valve port 216 providesa communication path between the inlet port 216 and the cylinder port210. An axial rod aperture 220 is aligned with the first valve port 218.A second valve port 222 provides communication between the exhaust port216 and the cylinder port 210. A second axial rod aperture 224 isaligned with the second valve port 222. Seals 226 mounted on the end ofthe axial rod apertures are identical to the seals 84. The specificconstruction of the valve ports 218 and 222 is identical to theconstruction of the valve ports in manifold block 22 set forth in detailabove.

Slideably mounted in the axial rod apertures 220 and 224 are valve rods228 and 230, respectively. The rods 228 and 230 have a nose identical tothe construction of the valve rods described in detail above. The rod228 is sealingly engageable with the first valve port 218 for regulatingthe flow through that port, and the rod 230 is engageable with thesecond valve port 222 for controlling the flow of fluid through thatvalve port.

The valve operator includes a pair of spring plungers 232 and 234 whichare identical in construction to the spring plungers 102 and 104. Thespring plunger 232 includes a hollow body 236 with a head 238 formedthereon. The head 238 has a cam surface 240 formed integral therewith. Adog pointed set screw 241 is threadedly mounted in the head 238 and maybe axially positioned relative to the plunger. The set screw 241 isengageable with rod 228 for axially positioning the rod. A compressionspring 242 is mounted on the hollow body 232 in engagement with the head238. The spring plunger 234 includes a hollow body 244 and a head 246formed integral therewith. A cam surface 248 is formed on the head 246.A compression spring 250 is mounted on the hollow body 244 in engagementwith the head 246. A dog pointed set screw 251 is threadedly mounted inthe head 246 so that it may be positioned axially relative to the springplunger. The set screw 251 is engageable with rod 230 for positioningthe rod.

A cam 252 is rotatably mounted in the cam block 204 and is engageablewith the cam surfaces 240 and 248. The cam is connected to an arm 254and handle 256, whereby the cam is positioned relative to the camsurfaces.

A plurality of screws 258 which are identical to screws 96 hold the camblock and the spring block in engagement with each other and mountedonto the manifold block 202.

The valve 200 is adjusted in the same manner in which the valve isadjusted so that the force of the springs 242 and 250, applied to theplunger rods, is transmitted by the valve rods axially relative to thesprings. In order to release one of the valves, the handle 256 isrotated so that the cam 252 retracts either one or the other of thespring plungers and allows the fluid to flow through the appropriatevalve port. It should be noted that as with the aforementioned valve 20,the fluid flow is against the valve rod so that the throttling may bequite close.

The valve 200 is also adjustable to an open center in the same manner inwhich valve 20 is adjusted. The set screws 241 and 251 are adjusted intheir respective plunger heads 238 and 246 so that the heads are inengagement with the cam 252 while the rods are out of contact with theirrespective valve ports. When the cam 252 is rotated, one of the rods isforced to move into closing engagement with its respective valve port.

Although a specific embodiment of the instant invention has been shownand described in detail above, it is readily apparent that those skilledin the art may make various modifications and changes in the presentinvention without departing from the spirit and scope thereof. It is. tobe expressly understood that the specific disclosure set forth is solelyfor purposes of illustration in accordance with the applicable patentlaws and is in no way deemed to limit the scope of the presentinvention. The instant invention is limited only by the appended claims.

What is claimed is:

1. A valve comprising: a manifold having an exhaust port, an inlet port,a first cylinder port, a second cylinder port, a first valve portproviding a communication path between the inlet port and the firstcylinder port, a second valve port providing a communication pathbetween the exhaust port and the first cylinder port, a third valve portproviding a communication path between the inlet port and the secondcylinder port, and a fourth valve port providing a communication pathbetween the second cylinder port and the exhaust port; a first valve rodslideably mounted in the manifold and sealingly engageable with thefirst valve port for releasably closing said port; a second valve rodslideably mounted in the manifold and sealingly engageable with thesecond valve port for releasably closing said port; a third valve rodslideably mounted in the manifold and sealingly engageable with thethird valve port for releasably closing said port; a fourth valve rodslideably mounted in the manifold and sealingly engageable with thefourth valve port for releasably closing said port; a first yokepivotedly engaging the first and fourth valve rods; a first springconnected to the first yoke, urging the first and fourth valve rods intosealing engagement with their respective ports; a second yoke pivotedlyengaging the second and third valve rods; a second spring connected tothe second yoke, urging the second and third valve rods into sealingengagement with their respective valve ports; and means for selectivelyrelieving the springs to allow the valve rods to disengage theirrespective valve ports.

2. A valve as defined in claim 1 wherein each of the springs is acompression spring, and including a spring plunger having a bodypositioned in each of the springs and a head engaging one end of itsrespective spring,

and a pivot pin mounted on each of the spring plungers and pivotedlyengaging its respective yoke.

3. A valve as defined in claim 2 wherein the pivot pin is axiallypositionable relative to the spring plunger to regulate the forceapplied by the compression spring.

4. A valve as defined in claim 3, including a tapered nose formedintegral with one end of each of the valve rods, each tapered nose beingcooperative with its respective valve port for regulating the flow of afluid through the valve port by the axial position of the tapered noserelative to the valve port.

5. A valve as defined in claim 4, including a cam engageable with thespring plungers for selectively retracting each of the spring plungersagainst the force of the respective compression springs.

6. A valve as defined in claim 2, including a cam engageable with thespring plungers for selectively retracting one of the spring plungersagainst the force of the respective compression spring.

7. A valve as defined in claim 1 wherein each of the valve rods has atapered nose on one end thereof extending axially from the valve rod,each said tapered nose being cooperative with its respective valve portfor regulating the flow of fluid through its respective valve port.

8. A valve as defined in claim 7, including a tapered crown between thevalve rod and its respective nose on each of the valve rods, a taperedvalve seat in each of the valve ports, each of the valve seats having anangle of taper slightly greater than the angle of taper of itsrespective tapered crown prior to the initial assembly thereof to allowcoining of the crown and seat during initial assembly.

9. A valve as defined in claim 1, including a pivot pin connected toeach of the springs between the spring and its respective yoke, each ofthe pivot pins being axially positionable relative to the spring toregulate the amount of spring force applied by the spring to therespective yoke, each of said pivot pins being pivotedly engageable withits respective yoke to allow the yoke to pivot about the pivot pin inresponse to forces applied to the yoke by its respective pair of valverods.

10. A valve as defined in claim 9, including a tapered nose formedintegral with one end of each of the valve rods, each tapered nose beingcooperative with its respective valve port to regulate the flow of fluidthrough the valve port by axial displacement thereof relative to thevalve port.

11. A valve as defined in claim 1, including a pivot connected to eachspring, said pivot pivotedly engaging its respective yoke to allow theyoke to pivot in response to forces applied to the yoke by itsrespective pair of valve rods.

12. A valve as defined in claim 11 wherein each of the valve rodsincludes a tapered noseformed integral with one end of each of the rods,each tapered nose being cooperative with its respective valve port forregulating flow of fluid through the valve port by axial displacementthereof relative to the respective valve port.

13. A valve as defined in claim 1 wherein each of the valve rods movesaxially to'open and to close its respective valve port and the directionof axial movement for opening the respective valve port is in the samedirection as the direction of flow of fluid through the valve port.

M. A valve comprising; a manifold having a cylinder port, an inlet port,a first valve port providing a communicating path between the cylinderport and the inlet port, an exhaust port, and a second valve portproviding a communicating path between the cylinder port and the exhaustport; a first rod slideably mounted in the manifold and sealinglyengageable with the first valve port to close selectively said valveport; a second valve rod slideably mounted in the manifold and sealinglyengageable with the second valve port for closing selectively saidsecond valve port; each of the valve rods has a tapered nose on one endthereof extending axially from the valve rod, each of said tapered nosesbeing cooperative with its respective valve port for regulating the flowof fluid through its respective valve port; a tapered crown between eachof the valve rods and its respective nose, and a tapered valve seat ineach of the valve ports,-each of the valve seats having an angle oftaper slightly greater than the angle of taper of its respective taperedcrown prior to the initial assembly thereof to allow coining of thecrown and seat during initial assembly; and a spring connected to eachof the valve rods to urge the valve rods into a sealingly closedattitude with the respectiye valve orts.

15. A valve as defined in claim 14 w ereln prior to initial assembly theangle of taper of the valve seat is /2 greater than the angle of taperof its respective tapered crown.

to. A valve comprising; a manifold having a cylinder port, an inletport, a first valve port providing a communicating path between thecylinder port and the inlet port, an exhaust port, and a second valveport providing a communicating path between the cylinder port and theexhaust port; a first rod slideably mounted in the manifold andsealingly engageable with the first valve port to close selectively saidvalve port; a second valve rod slideably 'mounted in the manifold andsealingly engageable with the second valve port for closing selectivelysaid second valve port; a spring connected to each of the valve rods tourge the valve rods into a sealingly closed attitude with the respectivevalve ports; and a spring plunger connected to each of the springs and aset screw connected to each of the valve rods for axial positioning ofthe valve rod relative to the spring plunger.

17. A valve as defined in claim 16, including a cam selectivelyengageable with each of the spring plungers to move a selected springplunger against the force of its respective spring.

13. A valve comprising; a manifold block including a cylinder port, aninlet port, a first valve port providing a communicating path betweenthe cylinder port and the inlet port, an exhaust port, and a secondvalve port providing a communicating path between the cylinder port andthe exhaust port; a cam block mounted on the manifold block; a pair ofvalve rods slideably mounted in the cam block and the manifold block;each of said valve rods being cooperative, respectively, with one of thefirst and second valve ports for regulating the flow of fluid throughthe valve ports; a spring block mounted on the cam block; a pair ofspring plungers slideably mounted in the spring block, each of thespring plungers being connected, respectively, to one of the valve rods;a compression spring mounted on each of the spring plungers; each of thevalve rods has a tapered nose on one end thereof extending axially fromthe valve rod, each of said tapered noses being cooperative with itsrespective valve port for regulating the flow of fluid through itsrespective valve port; a tapered crown between each of the valve rodsand its respective nose, a tapered valve seat in each of the valveports, each of the valve seats having an angle of taper slightly greaterthan the angle of taper of its respective tapered crown prior to theinitial assembly thereof to allowcoining of the crown and seat duringinitial assembly; and a cam mounted in the cam block and beingengageable with the spring plungers to retract selectively one of thespring plungers to allow a selected valve rod to open.

f i ll ll i"

1. A valve comprising: a manifold having an exhaust port, an inlet port,a first cylinder port, a second cylinder port, a first valve portproviding a communication path between the inlet port and the firstcylinder port, a second valve port providing a communication pathbetween the exhaust port and the first cylinder port, a third valve portproviding a communication path between the inlet port and the secondcylinder port, and a fourth valve port providing a communication pathbetween the second cylinder port and the exhaust port; a first valve rodslideably mounted in the manifold and sealingly engageable with thefirst valve port for releasably closing said port; a second valve rodslideably mounted in the manifold and sealingly engageable with thesecond valve port for releasably closing said port; a third valve rodslideably mounted in the manifold and sealingly engageable with thethird valve port for releasably closing said port; a fourth valve rodslideably mounted in the manifold and sealingly engageable with thefourth valve port for releasably closing said port; a first yokepivotedly engaging the first and fourth valve rods; a first springconnected to the first yoke, urging the first and fourth valve rods intosealing engagement with their respective ports; a second yoke pivotedlyengaging the second and third valve rods; a second spring connected tothe second yoke, urging the second and third valve rods into sealingengagement with their respective valve ports; and means for selectivelyrelieving the springs to allow the valve rods to disengage theirrespective valve ports.
 2. A valve as defined in claim 1 wherein each ofthe springs is a compression spring, and including a spring plungerhaving a body positioned in each of the springs and a head engaging oneend of its respective spring, and a pivot pin mounted on each of thespring plungers and pivotedly engaging its respective yoke.
 3. A valveas defined in claim 2 wherein the pivot pin is axially positionablerelative to the spring plunger to regulate the force applied by thecompression spring.
 4. A valve as defined in claim 3, including atapered nose formed integral with one end of each of the valve rods,each tapered nose being cooperative with its respective valve port forregulating the flow of a fluid through the valve port by the axialposition of the tapered nose relative to the valve port.
 5. A valve asdefined in claim 4, including a cam engageable with the spring plungersfor selectively retracting each of the spring plungers against the forceof the respective compression springs.
 6. A valve as defined in claim 2,including a cam engageable with the spring plungers for selectivelyretracting one of the spring plungers against the force of therespective compression spring.
 7. A valve as defined in claim 1 whereineach of the valve rods has a tapered nose on one end thEreof extendingaxially from the valve rod, each said tapered nose being cooperativewith its respective valve port for regulating the flow of fluid throughits respective valve port.
 8. A valve as defined in claim 7, including atapered crown between the valve rod and its respective nose on each ofthe valve rods, a tapered valve seat in each of the valve ports, each ofthe valve seats having an angle of taper slightly greater than the angleof taper of its respective tapered crown prior to the initial assemblythereof to allow coining of the crown and seat during initial assembly.9. A valve as defined in claim 1, including a pivot pin connected toeach of the springs between the spring and its respective yoke, each ofthe pivot pins being axially positionable relative to the spring toregulate the amount of spring force applied by the spring to therespective yoke, each of said pivot pins being pivotedly engageable withits respective yoke to allow the yoke to pivot about the pivot pin inresponse to forces applied to the yoke by its respective pair of valverods.
 10. A valve as defined in claim 9, including a tapered nose formedintegral with one end of each of the valve rods, each tapered nose beingcooperative with its respective valve port to regulate the flow of fluidthrough the valve port by axial displacement thereof relative to thevalve port.
 11. A valve as defined in claim 1, including a pivotconnected to each spring, said pivot pivotedly engaging its respectiveyoke to allow the yoke to pivot in response to forces applied to theyoke by its respective pair of valve rods.
 12. A valve as defined inclaim 11 wherein each of the valve rods includes a tapered nose formedintegral with one end of each of the rods, each tapered nose beingcooperative with its respective valve port for regulating flow of fluidthrough the valve port by axial displacement thereof relative to therespective valve port.
 13. A valve as defined in claim 1 wherein each ofthe valve rods moves axially to open and to close its respective valveport and the direction of axial movement for opening the respectivevalve port is in the same direction as the direction of flow of fluidthrough the valve port.
 14. A valve comprising; a manifold having acylinder port, an inlet port, a first valve port providing acommunicating path between the cylinder port and the inlet port, anexhaust port, and a second valve port providing a communicating pathbetween the cylinder port and the exhaust port; a first rod slideablymounted in the manifold and sealingly engageable with the first valveport to close selectively said valve port; a second valve rod slideablymounted in the manifold and sealingly engageable with the second valveport for closing selectively said second valve port; each of the valverods has a tapered nose on one end thereof extending axially from thevalve rod, each of said tapered noses being cooperative with itsrespective valve port for regulating the flow of fluid through itsrespective valve port; a tapered crown between each of the valve rodsand its respective nose, and a tapered valve seat in each of the valveports, each of the valve seats having an angle of taper slightly greaterthan the angle of taper of its respective tapered crown prior to theinitial assembly thereof to allow coining of the crown and seat duringinitial assembly; and a spring connected to each of the valve rods tourge the valve rods into a sealingly closed attitude with the respectivevalve ports.
 15. A valve as defined in claim 14 wherein prior to initialassembly the angle of taper of the valve seat is 1/2 * greater than theangle of taper of its respective tapered crown.
 16. A valve comprising;a manifold having a cylinder port, an inlet port, a first valve portproviding a communicating path between the cylinder port and the inletport, an exhaust port, and a second valve port providing a communicatingpath between the cylinder port and the exhaust port; a first rodsLideably mounted in the manifold and sealingly engageable with thefirst valve port to close selectively said valve port; a second valverod slideably mounted in the manifold and sealingly engageable with thesecond valve port for closing selectively said second valve port; aspring connected to each of the valve rods to urge the valve rods into asealingly closed attitude with the respective valve ports; and a springplunger connected to each of the springs and a set screw connected toeach of the valve rods for axial positioning of the valve rod relativeto the spring plunger.
 17. A valve as defined in claim 16, including acam selectively engageable with each of the spring plungers to move aselected spring plunger against the force of its respective spring. 18.A valve comprising; a manifold block including a cylinder port, an inletport, a first valve port providing a communicating path between thecylinder port and the inlet port, an exhaust port, and a second valveport providing a communicating path between the cylinder port and theexhaust port; a cam block mounted on the manifold block; a pair of valverods slideably mounted in the cam block and the manifold block; each ofsaid valve rods being cooperative, respectively, with one of the firstand second valve ports for regulating the flow of fluid through thevalve ports; a spring block mounted on the cam block; a pair of springplungers slideably mounted in the spring block, each of the springplungers being connected, respectively, to one of the valve rods; acompression spring mounted on each of the spring plungers; each of thevalve rods has a tapered nose on one end thereof extending axially fromthe valve rod, each of said tapered noses being cooperative with itsrespective valve port for regulating the flow of fluid through itsrespective valve port; a tapered crown between each of the valve rodsand its respective nose, a tapered valve seat in each of the valveports, each of the valve seats having an angle of taper slightly greaterthan the angle of taper of its respective tapered crown prior to theinitial assembly thereof to allow coining of the crown and seat duringinitial assembly; and a cam mounted in the cam block and beingengageable with the spring plungers to retract selectively one of thespring plungers to allow a selected valve rod to open.